using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using D3ROVoice.Api.Data;
using D3ROVoice.Api.Dtos;
using D3ROVoice.Api.Services;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace D3ROVoice.Api.Controllers;

[ApiController]
[Route("api/[controller]")]
public class AdminController : ControllerBase
{
    private readonly AppDbContext _db;
    private readonly ISttProxyService _sttService;
    private static readonly DateTime _serverStartTime = DateTime.UtcNow;

    public AdminController(AppDbContext db, ISttProxyService sttService)
    {
        _db = db;
        _sttService = sttService;
    }

    [HttpGet("stats")]
    public async Task<IActionResult> GetStats()
    {
        var totalUsers = await _db.Users.CountAsync();
        var today = DateTime.UtcNow.Date;
        var activeUsersToday = await _db.Users.CountAsync(u => u.LastLoginAt >= today);
        var totalRequests = await _db.UsageLogs.CountAsync() + await _db.SttUsageLogs.CountAsync();
        var totalLlmCost = await _db.UsageLogs.SumAsync(u => (decimal?)u.CalculatedCost) ?? 0m;
        var totalSttCost = await _db.SttUsageLogs.SumAsync(u => (decimal?)u.CalculatedCost) ?? 0m;
        var totalCost = totalLlmCost + totalSttCost;
        var errorCount = await _db.ErrorLogs.CountAsync();

        var recentErrors = await _db.ErrorLogs
            .OrderByDescending(e => e.CreatedAt)
            .Take(10)
            .Select(e => new ServerErrorLogDto(e.Id, e.ErrorType, e.Message, e.Endpoint, e.CreatedAt))
            .ToListAsync();

        var uptime = (DateTime.UtcNow - _serverStartTime).TotalSeconds;

        var stats = new ServerStatsDto(
            totalUsers,
            activeUsersToday,
            totalRequests,
            totalCost,
            uptime,
            errorCount,
            recentErrors
        );

        return Ok(stats);
    }

    [HttpGet("users")]
    public async Task<IActionResult> GetUsers()
    {
        var users = await _db.Users
            .OrderByDescending(u => u.CreatedAt)
            .Select(u => new UserInfoDto(u.Id, u.Email, u.Role, u.CreatedAt, u.LastLoginAt, u.IsActive))
            .ToListAsync();

        return Ok(users);
    }

    // ── LLM Model Endpoints ───────────────────────────────────────────────

    [HttpGet("endpoints")]
    public async Task<IActionResult> GetEndpoints()
    {
        var endpoints = await _db.ModelEndpoints
            .OrderBy(m => m.Id)
            .ToListAsync();

        return Ok(endpoints);
    }

    [HttpPost("endpoints")]
    public async Task<IActionResult> CreateEndpoint([FromBody] CreateModelEndpointDto dto)
    {
        if (string.IsNullOrWhiteSpace(dto.ModelId) || string.IsNullOrWhiteSpace(dto.ModelName))
        {
            return BadRequest(new { message = "ModelId와 ModelName은 필수 항목입니다." });
        }

        var existing = await _db.ModelEndpoints.FirstOrDefaultAsync(m => m.ModelId == dto.ModelId);
        if (existing != null)
        {
            return Conflict(new { message = "이미 존재하는 ModelId입니다." });
        }

        var endpoint = new ServiceModelEndpoint
        {
            ModelId = dto.ModelId.Trim(),
            ModelName = dto.ModelName.Trim(),
            Provider = dto.Provider.Trim(),
            EndpointUrl = dto.EndpointUrl.Trim(),
            ApiKey = dto.ApiKey ?? "",
            CostPer1kPromptTokens = dto.CostPer1kPromptTokens,
            CostPer1kCompletionTokens = dto.CostPer1kCompletionTokens,
            IsActive = true,
            CreatedAt = DateTime.UtcNow
        };

        _db.ModelEndpoints.Add(endpoint);
        await _db.SaveChangesAsync();

        return Ok(endpoint);
    }

    [HttpPut("endpoints/{id}")]
    public async Task<IActionResult> UpdateEndpoint(int id, [FromBody] UpdateModelEndpointDto dto)
    {
        var endpoint = await _db.ModelEndpoints.FindAsync(id);
        if (endpoint == null) return NotFound();

        endpoint.ModelName = dto.ModelName.Trim();
        endpoint.Provider = dto.Provider.Trim();
        endpoint.EndpointUrl = dto.EndpointUrl.Trim();
        endpoint.ApiKey = dto.ApiKey ?? "";
        endpoint.CostPer1kPromptTokens = dto.CostPer1kPromptTokens;
        endpoint.CostPer1kCompletionTokens = dto.CostPer1kCompletionTokens;
        endpoint.IsActive = dto.IsActive;

        await _db.SaveChangesAsync();
        return Ok(endpoint);
    }

    [HttpDelete("endpoints/{id}")]
    public async Task<IActionResult> DeleteEndpoint(int id)
    {
        var endpoint = await _db.ModelEndpoints.FindAsync(id);
        if (endpoint == null) return NotFound();

        _db.ModelEndpoints.Remove(endpoint);
        await _db.SaveChangesAsync();

        return Ok(new { message = "삭제되었습니다." });
    }

    // ── STT / Transcription Provider Endpoints ────────────────────────────

    [HttpGet("stt-endpoints")]
    public async Task<IActionResult> GetSttEndpoints()
    {
        var endpoints = await _sttService.GetAllEndpointsAsync();
        return Ok(endpoints);
    }

    [HttpGet("stt-endpoints/{id}")]
    public async Task<IActionResult> GetSttEndpoint(int id)
    {
        var endpoints = await _sttService.GetAllEndpointsAsync();
        var endpoint = endpoints.FirstOrDefault(e => e.Id == id);
        if (endpoint == null) return NotFound(new { message = $"STT Endpoint {id} not found." });
        return Ok(endpoint);
    }

    [HttpPost("stt-endpoints")]
    public async Task<IActionResult> CreateSttEndpoint([FromBody] CreateSttEndpointDto dto)
    {
        if (string.IsNullOrWhiteSpace(dto.Name) || string.IsNullOrWhiteSpace(dto.EndpointUrl))
        {
            return BadRequest(new { message = "이름과 Endpoint URL은 필수입니다." });
        }

        var endpoint = await _sttService.CreateEndpointAsync(dto);
        return Ok(endpoint);
    }

    [HttpPut("stt-endpoints/{id}")]
    public async Task<IActionResult> UpdateSttEndpoint(int id, [FromBody] UpdateSttEndpointDto dto)
    {
        try
        {
            var endpoint = await _sttService.UpdateEndpointAsync(id, dto);
            return Ok(endpoint);
        }
        catch (KeyNotFoundException)
        {
            return NotFound(new { message = $"STT Endpoint {id} not found." });
        }
    }

    [HttpDelete("stt-endpoints/{id}")]
    public async Task<IActionResult> DeleteSttEndpoint(int id)
    {
        var deleted = await _sttService.DeleteEndpointAsync(id);
        if (!deleted) return NotFound();
        return Ok(new { message = "STT 엔드포인트가 성공적으로 삭제되었습니다." });
    }

    [HttpPost("stt-endpoints/{id}/set-default")]
    public async Task<IActionResult> SetDefaultSttEndpoint(int id)
    {
        var success = await _sttService.SetDefaultEndpointAsync(id);
        if (!success) return NotFound();
        return Ok(new { id, isDefault = true, success = true, message = "기본 클라우드 전사 프로바이더로 설정되었습니다." });
    }

    [HttpPost("stt-endpoints/{id}/test")]
    public async Task<IActionResult> TestSttEndpoint(int id)
    {
        var result = await _sttService.TestEndpointAsync(id);
        return Ok(result);
    }

    [HttpPost("stt-endpoints/test-direct")]
    public async Task<IActionResult> TestSttDirect([FromQuery] string endpointUrl, [FromQuery] string? apiKey)
    {
        var result = await _sttService.TestEndpointAsync(0, apiKey, endpointUrl);
        return Ok(result);
    }

    [HttpGet("stt-usage")]
    public async Task<IActionResult> GetSttUsageReport()
    {
        var report = await _sttService.GetUsageReportAsync();
        return Ok(report);
    }

    // ── LLM Usage Report ──────────────────────────────────────────────────

    [HttpGet("usage")]
    public async Task<IActionResult> GetUsageReport()
    {
        var logs = await _db.UsageLogs.AsNoTracking().ToListAsync();

        var totalRequests = logs.Count;
        var totalPromptTokens = logs.Sum(l => l.PromptTokens);
        var totalCompletionTokens = logs.Sum(l => l.CompletionTokens);
        var totalCost = logs.Sum(l => l.CalculatedCost);

        var userSummaries = logs
            .GroupBy(l => new { l.UserId, l.UserEmail })
            .Select(g => new UserUsageSummaryDto(
                g.Key.UserId,
                g.Key.UserEmail,
                g.Count(),
                g.Sum(x => x.TotalTokens),
                g.Sum(x => x.CalculatedCost)
            ))
            .OrderByDescending(u => u.TotalCost)
            .ToList();

        var modelSummaries = logs
            .GroupBy(l => l.ModelId)
            .Select(g => new ModelUsageSummaryDto(
                g.Key,
                g.Key,
                g.Count(),
                g.Sum(x => x.TotalTokens),
                g.Sum(x => x.CalculatedCost)
            ))
            .OrderByDescending(m => m.TotalCost)
            .ToList();

        var report = new UsageReportDto(
            totalRequests,
            totalPromptTokens,
            totalCompletionTokens,
            totalCost,
            userSummaries,
            modelSummaries
        );

        return Ok(report);
    }
}